Conventionally, as a power converter for an electric system or electric assist systems for vehicles, a DC/DC converter has been disclosed which can vary a boosting (bucking) ratio with a magnetic cancellation type transformer (see, for example, patent document 1). The DC/DC converter has such a configuration that a boosting-and-bucking-ratio-variable inductor and a magnetic field cancellation type of transformer are disposed between an input terminal and a plurality of switching elements.
Such a configuration provides continuous boosting-bucking operations and down-sizes the inductor and the transformer, which provides a small size and light weight boosting-bucking type of DC/DC converter.